Python Built-in Boolean Functions

The Python interpreter has some built-in boolean functions.

all()

all(iterable)

Parameters

all()to return a True if all elements of the specified iterable are true. iterableto specify the iterable to be returned from

Remarks

• If all elements of the object are true or the object is empty, then all() returns True
• Equivalent to: def all(iterable): for element in iterable: if not element: return False return True

any()

any(iterable)

Parameters

any()to return a True if any elements of the specified object are true and the object is not empty.

Remarks

• If the iterable is empty, return False.
• If any element of the iterable is true
• Equivalent to: def any(iterable): for element in iterable: if element: return True return False

callable()

callable(object)

Parameters

callable()to return True if the specified object appears callable. objectto specify the object to be returned from

Remarks

• If object appears callable, return True
• Is object appears not callable, return False
• A callable that returns True, is still possible that a call fails, but if a callable that returns False will never succeed to call the object.
• Classes are callable (calling a class returns a new instance), and instances are callable if their class has a __call__() method.

hasattr()

hasattr(object, name)

Parameters

hasattr()to return True if the specified name is one attribute of the specified object.

Remarks

• This is implemented by calling getattr(object, name) and seeing whether it raises an AttributeError or not.

isinstance()

isinstance(object, classinfo)

Parameters

isinstance()to return True if the specified object is an instance of the given classinfo, or of a direct, indirect, or virtual subclass thereof. objectto specify the object to be returned from classinfoto specify the type of object to be refered to

Remarks

• if object is an instance of the classinfo, or of a direct, indirect, or virtual ssubclass thereof, isinstance()returns True
• If object in not an object of the given type, isinstance() returns False
• If classinfo is a tuple of type objects or recursively, other such tuples, return True if object is an instance of any of the types.
• if classinfo is not a type or tuple of types and such tuples, a TypeError exception is raised.

issubclass()

issubclass(class, classinfo)

Parameters

issubclass()to return True if the specified class is a direct, indirect, or virtual subclass of classinfo classto specify the class to be returned from classinfoto specify the type of object to be refered to

Remarks

• A class is considered a subclass of itself.
• classinfo may be a tuple of class objects, in which case every entry in classinfo will be checked.
• classinfo of other case, a TypeError exception is raised.

Source and Reference

• https://docs.python.org/3/reference/executionmodel.html
• https://docs.python.org/2.0/ref/execframes.html
• https://docs.python.org/3/library/functions.html
• https://www.geeksforgeeks.org/classmethod-in-python/
• https://docs.python.org/3/library/stdtypes.html#typesmapping